Electron-correlation effects in the gg-factor of light Li-like ions

We investigate electron-correlation effects in the $g$-factor of the ground state of Li-like ions. Our calculations are performed within the nonrelativistic quantum electrodynamics (NRQED) expansion up to two leading orders in the fine-structure constant $\alpha$, $\alpha^2$ and $\alpha^3$. The dependence of the NRQED results on the nuclear charge number $Z$ is studied and the individual $1/Z$-expansion contributions are identified. Combining the obtained data with the results of the all-order (in $Z\alpha$) calculations performed within the $1/Z$ expansion, we derive the unified theoretical predictions for the $g$-factor of light Li-like ions.Comment: 9 pages, 4 table

Coefficients of Friction for Apple on Various Surfaces as Affected by Velocity

Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a Technical Paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 5 (2003): C. Puchalski, G. Brusewitz, and Z. Slipek. Coefficients of Friction for Apple on Various Surfaces as Affected by Velocity. Vol. V. December 2003

Field relations and petrology of the Trafalgar Plutonic Suite and comparisons with other Devonian granitoid plutons in the Meguma terrane, Nova Scotia, Canada

The Trafalgar Plutonic Suite intruded metasedimentary rocks of the Goldenville and Halifax groups in the northeastern part of the Meguma terrane of southern Nova Scotia at about 374 Ma, based on previously published U–Pb and 40Ar/39Ar mineral ages. Using field and petrographic observations, the suite is divided into 20 different plutons on the combined basis of variations in grain size (fine, medium, or coarse), texture (equigranular or porphyritic) and modal mineralogy (quartz diorite/tonalite, granodiorite, monzogranite, and syenogranite). The granodiorite, monzogranite, and syenogranite plutons are relatively uniform in composition with little variation in mineralogy or chemistry within each pluton or between plutons of the same lithology. In contrast the quartz diorite/tonalite plutons show mineralogical and chemical variation, both within and between plutons. The granodiorite, monzogranite, and syenogranite plutons closely resemble other peraluminous granitoid plutons characteristic of the Meguma terrane. The quartz diorite/tonalite plutons are varied but chemically resemble minor Devonian mafic intrusions elsewhere in the Meguma terrane. Like other plutons of the Meguma terrane, the Trafalgar Plutonic Suite has chemical characteristics of volcanic-arc to syn-collisional granitoid rocks and likely has experienced extensive contamination by metasedimentary material as documented by previous studies of plutons in the Meguma terrane. The minor quartz diorite/tonalite plutons are additional examples of the mafic rocks that have been proposed in tectonic models of the Meguma terrane to have facilitated melting of the lower crust to generate granodioritic parent magmas, followed by crystal fractionation and extensive contamination by metasedimentary material.La suite plutonique de Trafalgar s’est mise en place dans les roches métasédimentaires des groupes de Goldenville et Halifax dans la partie nord-est de la zone de Meguma au sud de la Nouvelle-Écosse à environ 374 Ma, d’après des âges U-Pb et 40Ar/39Ar déjà publiés. À partir d’observations sur le terrain et pétrographiques, la suite se divise en 20 plutons, basé sur un ensemble de caractéristiques telles que la variation granulométrique (fin, moyen ou grossier), la texture des roches (équidimensionnel ou porphyritique) et la proportion minéralogique (diorite quartzifère/tonalite, granodiorite, monzogranite et syénogranite). La composition des plutons constitués de granodiorite, de monzogranite et de syénogranite est relativement uniforme avec peu de variation minéralogique ou chimique au sein de chacun des plutons ou d’un pluton à un autre de lithologie semblable. En revanche, les plutons formés de diorite quartzifère/tonalite présentent des variations minéralogiques et chimiques à l’intérieur du même pluton et à travers la suite plutonique. Les plutons constitués de granodiorite, de monzogranite et de syénogranite ressemblent étroitement aux autres granitoïdes peralumineux de la zone de Meguma. Les plutons de diorite quartzifère/tonalite sont variables mais chimiquement comparables aux intrusions mafiques dévoniens retrouvés ailleurs dans la zone de Meguma. Comme plusieurs autres plutons de la zone de Meguma, la suite plutonique de Trafalgar possède des caractéristiques chimiques semblables aux granitoïdes de type arc volcanique à syncollisionnel et ayant sans doute subi une contamination significative des roches métasédimentaires, tels que documenté dans des études précédentes sur les plutons de la zone de Meguma. Les moins vastes plutons formés de diorite quartzifère/tonalite constituent des exemples supplémentaires de roches mafiques qui furent présentées dans des modèles tectoniques de la zone de Meguma comme ayant contribuées à la fusion de la croute inférieure et ainsi générer un magma parent granodioritique, suivi d’une cristallisation fractionnée combinée à une contamination importante provenant des roches métasédimentaires

Relativistic, QED, and nuclear mass effects in the magnetic shielding of 3^3He

The magnetic shielding $\sigma$ of $^3$He is studied. The complete relativistic corrections of order $O(\alpha^2)$, leading QED corrections of order $O(\alpha^3 \ln\alpha)$, and finite nuclear mass effects of order $O(m/m_{\rm N})$ are calculated with high numerical precision. The resulting theoretical predictions for $\sigma = 59.967~43(10)\cdot 10^{-6}$ are the most accurate to date among all elements and support the use of $^3$He as a NMR standard.Comment: 10 pages, corrected minor errors in Eqs.(6,7

Development of a Pain Management Protocol for a Paediatric Ward in the Gambia, West Africa

Despite recent advances in our understanding of paediatric pain and its management, pain continues to be undertreated globally, particularly in children and in low income countries. This article describes the development of a paediatric analgesia and sedation protocol, tailored to the specific setting of the Medical Research Council (MRC) paediatric ward in the Gambia, West Africa. An iterative process was used throughout development, with inputs from the medical literature, local providers, and pain experts, incorporated to ensure a safe, effective, and locally appropriate protocol. We demonstrate that evidence-based published guidelines, can and should be adapted to allow for optimal pain management given the resources and capabilities of specific health care settings. It is hoped that the process and protocol described here, will not only help to improve care on the MRC ward, but serve as an example to others working toward improving pain management in similar health care settings

Self-energy screening effects in the gg factor of Li-like ions

We report an investigation of the self-energy screening effects for the $g$ factor of the ground state of Li-like ions. The leading screening contribution of the relative order $1/Z$ is calculated to all orders in the binding nuclear strength parameter $Z\alpha$ (where $Z$ is the nuclear charge number and $\alpha$ is the fine-structure constant). We also extend the known results for the $Z\alpha$ expansion of the QED screening correction by deriving the leading logarithmic contribution of order $\alpha^5\ln\alpha$ and obtaining approximate results for the $\alpha^5$ and $\alpha^6$ contributions. The comparison of the two approaches yields a stringent check of consistency of the two calculations and allows us to obtain improved estimations of the higher-order screening effects.Comment: Several misprints are corrected in ver.3; Sec. VI is updated in ver.